feat: Add automated profit withdrawal system

- UI page: /withdrawals with stats dashboard and config form
- Settings API: GET/POST for .env configuration
- Stats API: Real-time profit and withdrawal calculations
- Execute API: Safe withdrawal with Drift SDK integration
- Drift service: withdrawFromDrift() with USDC spot market (index 0)
- Safety checks: Min withdrawal amount, min account balance, profit-only
- Telegram notifications: Withdrawal alerts with Solscan links
- Dashboard navigation: Added Withdrawals card (3-card grid)

User goal: 10% of profits automatically withdrawn on schedule
Current: Manual trigger ready, scheduled automation pending
Files: 5 new (withdrawals page, 3 APIs, Drift service), 2 modified

lib/drift/withdraw.ts

@@ -0,0 +1,160 @@
+/**
+ * Withdrawal Execution Service
+ * 
+ * Handles actual withdrawal from Drift Protocol to wallet
+ */
+
+import { BN } from '@project-serum/anchor'
+import { PublicKey } from '@solana/web3.js'
+import { initializeDriftService } from './client'
+
+export interface WithdrawalResult {
+  success: boolean
+  amount?: number
+  signature?: string
+  error?: string
+}
+
+export async function withdrawFromDrift(
+  amountUSD: number,
+  destinationWallet?: string
+): Promise<WithdrawalResult> {
+  try {
+    console.log(`💸 Initiating withdrawal: $${amountUSD.toFixed(2)}`)
+    
+    const driftService = await initializeDriftService()
+    
+    // Get USDC spot market index (typically 0 for USDC)
+    const usdcMarketIndex = 0
+    
+    // Convert USD amount to token amount (USDC has 6 decimals)
+    // $50.25 → 50,250,000 (raw token amount with 6 decimals)
+    const tokenAmount = new BN(Math.floor(amountUSD * 1_000_000))
+    
+    console.log(`📊 Withdrawal details:`)
+    console.log(`   Amount: $${amountUSD.toFixed(2)} USDC`)
+    console.log(`   Token amount: ${tokenAmount.toString()} (raw with 6 decimals)`)
+    console.log(`   Market index: ${usdcMarketIndex}`)
+    
+    // Get destination address (default to wallet public key if not specified)
+    const destination = destinationWallet 
+      ? new PublicKey(destinationWallet)
+      : new PublicKey(process.env.WALLET_PUBLIC_KEY!)
+    
+    console.log(`   Destination: ${destination.toString()}`)
+    
+    // Execute withdrawal via Drift SDK
+    // withdraw(amount, marketIndex, associatedTokenAddress, reduceOnly, subAccountId, txParams, updateFuel)
+    const signature = await driftService.getDriftClient().withdraw(
+      tokenAmount,
+      usdcMarketIndex,
+      destination,
+      false, // reduceOnly
+      0, // subAccountId
+      undefined, // txParams
+      false // updateFuel
+    )
+    
+    console.log(`✅ Withdrawal successful!`)
+    console.log(`   Transaction: ${signature}`)
+    console.log(`   Explorer: https://solscan.io/tx/${signature}`)
+    
+    // Confirm transaction
+    console.log('⏳ Confirming transaction on-chain...')
+    const connection = driftService.getConnection()
+    const confirmation = await connection.confirmTransaction(signature, 'confirmed')
+    
+    if (confirmation.value.err) {
+      throw new Error(`Transaction failed: ${JSON.stringify(confirmation.value.err)}`)
+    }
+    
+    console.log('✅ Transaction confirmed on-chain')
+    
+    return {
+      success: true,
+      amount: amountUSD,
+      signature,
+    }
+  } catch (error: any) {
+    console.error('❌ Withdrawal failed:', error)
+    return {
+      success: false,
+      error: error.message || 'Unknown error during withdrawal',
+    }
+  }
+}
+
+export async function calculateWithdrawalAmount(): Promise<{
+  availableProfit: number
+  withdrawalAmount: number
+  safeToWithdraw: boolean
+  reason?: string
+}> {
+  try {
+    const driftService = await initializeDriftService()
+    const health = await driftService.getAccountHealth()
+    const currentBalance = parseFloat(health.freeCollateral)
+    
+    // Configuration
+    const totalInvested = 546 // From roadmap
+    const withdrawalPercent = parseFloat(process.env.WITHDRAWAL_PROFIT_PERCENT || '10')
+    const minWithdrawalAmount = parseFloat(process.env.MIN_WITHDRAWAL_AMOUNT || '50')
+    const minAccountBalance = parseFloat(process.env.MIN_ACCOUNT_BALANCE || '500')
+    
+    // Calculate available profit
+    const availableProfit = Math.max(0, currentBalance - totalInvested)
+    const withdrawalAmount = availableProfit * (withdrawalPercent / 100)
+    
+    console.log(`💰 Withdrawal calculation:`)
+    console.log(`   Current balance: $${currentBalance.toFixed(2)}`)
+    console.log(`   Total invested: $${totalInvested.toFixed(2)}`)
+    console.log(`   Available profit: $${availableProfit.toFixed(2)}`)
+    console.log(`   Withdrawal %: ${withdrawalPercent}%`)
+    console.log(`   Withdrawal amount: $${withdrawalAmount.toFixed(2)}`)
+    console.log(`   Min withdrawal: $${minWithdrawalAmount.toFixed(2)}`)
+    console.log(`   Min account balance: $${minAccountBalance.toFixed(2)}`)
+    
+    // Safety checks
+    if (availableProfit <= 0) {
+      return {
+        availableProfit,
+        withdrawalAmount: 0,
+        safeToWithdraw: false,
+        reason: 'No profits available (current balance ≤ total invested)',
+      }
+    }
+    
+    if (withdrawalAmount < minWithdrawalAmount) {
+      return {
+        availableProfit,
+        withdrawalAmount,
+        safeToWithdraw: false,
+        reason: `Withdrawal amount ($${withdrawalAmount.toFixed(2)}) below minimum ($${minWithdrawalAmount.toFixed(2)})`,
+      }
+    }
+    
+    const balanceAfterWithdrawal = currentBalance - withdrawalAmount
+    if (balanceAfterWithdrawal < minAccountBalance) {
+      return {
+        availableProfit,
+        withdrawalAmount,
+        safeToWithdraw: false,
+        reason: `Withdrawal would drop balance to $${balanceAfterWithdrawal.toFixed(2)} (below minimum $${minAccountBalance.toFixed(2)})`,
+      }
+    }
+    
+    return {
+      availableProfit,
+      withdrawalAmount,
+      safeToWithdraw: true,
+    }
+  } catch (error: any) {
+    console.error('❌ Withdrawal calculation failed:', error)
+    return {
+      availableProfit: 0,
+      withdrawalAmount: 0,
+      safeToWithdraw: false,
+      reason: error.message,
+    }
+  }
+}